α-Alkyldibenzylketones included in cation exchanged faujasite type zeolites show photobehavior different from that in isotropic organic solvents. Rearrangement and disproportionation which do not contribute in solution are the major processes within the cavities of faujasites. Cation size plays a major role in controlling the pathway pursued by the primary and the secondary radical pair.
Templation of the Excited-State Chemistry of α-(<i>n</i>-Alkyl) Dibenzyl Ketones: How Guest Packing within a Nanoscale Supramolecular Capsule Influences Photochemistry
作者:Corinne L. D. Gibb、Arun Kumar Sundaresan、V. Ramamurthy、Bruce C. Gibb
DOI:10.1021/ja7107917
日期:2008.3.1
resulted from the well-known Norrish type I reaction. However, within the capsule the excited-state chemistry of the eight ketones was dependent on the alkylchainlength. The first group consisted of alpha-hexyl, alpha-heptyl, and alpha-octyl dibenzyl ketones that yielded large amounts of Norrish type II products within the host, while in solution the major products were from Norrish type I reaction
已经在各向同性溶液和水溶性胶囊中探索了能够进行 II 型和/或 I 型光反应的八种 α-烷基二苄基酮(烷基 = CH3 到 n-C8H17)的激发态行为。该研究由两部分组成:探索激发态化学的光化学和揭示胶囊内每个客体包装的核磁共振分析。核磁共振数据(COSY、NOESY 和 TOCSY 实验)表明,α-烷基二苄基酮与由两个空腔形成的胶囊之间的三元配合物在动力学上是稳定的,客体分为三个由 α-烷基长度调节的填充基序链。本质上,宿主充当外部模板,以促进形成不同的客体构象异构体。所有八位客体在己烷或缓冲溶液中辐照后的主要产物来自众所周知的 Norrish I 型反应。然而,在胶囊内,八种酮的激发态化学取决于烷基链长度。第一组由α-己基、α-庚基和α-辛基二苄基酮组成,在宿主内产生大量Norrish II 型产物,而在溶液中,主要产物来自Norrish I 型反应。第二组由α-丁基和α-戊基二苄基
Modification of photochemical reactivity by zeolites. A comparison between zeolite-solvent slurry and dry solid photolyses
作者:V. Ramamurthy、D. R. Corbin、N. J. Turro、Z. Zhang、M. A. Garcia Garibay
DOI:10.1021/jo00001a048
日期:1991.1
The use of a zeolite-solvent slurry as a convenient medium to carry out photoreactions is illustrated with four examples, namely Norrish type I reaction of dibenzyl ketones, Norrish type I and type II reactions of alpha-alkylbenzyl benzyl ketones, Norrish type II reaction of aryl alkyl ketones, and photodimerization of acenaphthylene. Solvent present within the supercages of zeolites X and Y provides constraint on the mobility of the included guest molecules. Such restrictions are reflected in the product distributions. The difference in the product distribution obtained between the zeolite-solvent slurry and a homogeneous solution is often higher than that between the dry powder zeolites and a homogeneous solution.
Modification of photochemical reactivity by zeolites. Norrish type I and type II reactions of ketones as photochemical probes of the interior of zeolites